# std::filesystem::directory_entry::assign

From cppreference.com
< cpp‎ | filesystem‎ | directory entry

void assign( const std::filesystem::path& p ); | (1) | (since C++17)
void assign( const std::filesystem::path& p, std::error_code& ec ); | (2) | (since C++17)

Assigns new content to the directory entry object. Sets the path to p and calls `refresh` to update the cached attributes. If an error occurs, the values of the cached attributes are unspecified.

This function does not commit any changes to the filesystem.

### Parameters

p | - | path to the filesystem object to which the directory entry will refer
ec | - | out-parameter for error reporting in the non-throwing overload

### Return value

(none)

### Exceptions

Any overload not marked `noexcept` may throw std::bad_alloc if memory allocation fails.

1) Throws std::filesystem::filesystem_error on underlying OS API errors, constructed with p as the first path argument and the OS error code as the error code argument.
2) Sets a std::error_code& parameter to the OS API error code if an OS API call fails, and executes ec.`clear`() if no errors occur.

### Example

Run this code

    #include <filesystem>
    #include <fstream>
    #include <iostream>

    void print_entry_info(const std::filesystem::directory_entry& entry)
    {
        if (std::cout << "The entry " << entry; not entry.exists())
        {
            std::cout << " does not exists on the file system\n";
            return;
        }
        std::cout << " is ";
        if (entry.is_directory())
            std::cout << "a directory\n";
        if (entry.is_regular_file())
            std::cout << "a regular file\n";
        /*...*/
    }

    int main()
    {
        std::filesystem::current_path(std::filesystem::temp_directory_path());

        std::filesystem::directory_entry entry{std::filesystem::current_path()};
        print_entry_info(entry);

        std::filesystem::path name{"cppreference.html"};
        std::ofstream{name} << "C++";

        std::cout << "entry.assign();\n";
        entry.assign(entry/name);
        print_entry_info(entry);

        std::cout << "remove(entry);\n";
        std::filesystem::remove(entry);
        print_entry_info(entry); // the entry still contains old "state"

        std::cout << "entry.assign();\n";
        entry.assign(entry); // or just call entry.refresh()
        print_entry_info(entry);
    }

Possible output:

    The entry "/tmp" is a directory
    entry.assign();
    The entry "/tmp/cppreference.html" is a regular file
    remove(entry);
    The entry "/tmp/cppreference.html" is a regular file
    entry.assign();
    The entry "/tmp/cppreference.html" does not exists on the file system

### See also

operator= | assigns contents (public member function)

Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/filesystem/directory_entry/assign&oldid=158088"